1. Field of Invention
The present invention relates to a spare-tire fastening structure for fastening a spare-tire to a support member in a spare-tire receiving section by engaging a bolt member with a nut member anchored to the support member such as a bracket.
2. Description of Prior Art
Generally, when a spare-tire is to be fastened to a support member such as a bracket in a spare-tire receiving section of an automobile, a mounting hole of a wheel of the spare-tire is aligned with a nut welded to the support member, and then a bolt member is inserted through the mounting hole and is screwed into the nut. This operation takes long time for screwing the bolt member and accordingly, makes poor working efficiency. In order to solve this problem, Japanese Utility Model Registration No. 2583778 (Japanese Utility Model Publication No. 05-022279) discloses a improved fastening structure in which a plastic nut member is fixed to a boss in a spare-tire receiving section and a bolt member is inserted into the nut member to fasten the spare-tire thereto. Since this fastening structure allows the spare-tire to be fastened only by press-inserting the bolt member into the nut member, a screwing operation of the bolt member can be eliminated or reduced greatly to improve the working efficiency.
The fastening structure disclosed in the above Utility Model publication, however, is configured to attach the nut member to the boss as the support member in the spare-tire receiving section from an under surface side of the boss, and this makes an attaching operation troublesome since it is required to stretch one hand to a back side of the boss. Further, since the nut member is attached to the boss from the under surface side thereof, an inserting force of the bolt member into the nut member is applied to the nut member in a direction to disengage it from the boss, and therefore this structure is not preferable since there is a fear that the nut member might be disengaged from the boss by a strong inserting force applied thereto by the bolt member. Spare-tire fastening structures other than that of the above Utility Model publication are disclosed in Japanese Utility Model Publication Nos. 60-070480 and 61-190782.
The spare-tire fastening structure disclosed in the Utility Model Publication No. 60-70480 has a bar disposed in the spare-tire receiving section with a base portion thereof being fixed to a certain portion therein, and the spare-tire is placed with the bar being inserted into the mounting hole of the spare-tire wheel, and then a special fitting is attached to a top end of the bar projected through the mounting hole of the wheel to fasten the spare-tire. This fastening structure does not use a nut member and a bolt member for fastening but requires welding the bar to the spare-tire receiving section and also requires the special fitting. In the spare-tire fastening structure disclosed in the Utility Model Publication No. 61-190782, a housing member made of metal is fixed to a certain portion of the spare-tire receiving section by, for example, welding, and a pair of half nut blocks made of metal, which cooperate to function as a complete nut, and a metal spring for biasing the pair of half nut blocks upward are disposed within the housing member to make up a nut member as a whole, so that the spare-tire may be fastened by placing the spare-tire with the mounting hole of the spare-tire wheel being aligned with the nut member and then by inserting the bolt member into the nut member. This fastening structure requires a welding operating for fixing the housing of the nut member to the spare-tire receiving section and an assembling operation for attaching the metal half nut blocks and the metal spring to the housing to be held therein after the housing has been fixed to the spare-tire receiving section, and further, the metal members may cause a rusting problem.
U.S. Pat. No. 5,586,698 discloses a structure in which a service tool such as a wheel wrench may be held by a holder in the spare-tire receiving section. It is convenient that the spare-tire receiving section is provided with the tool holding portion, but in this publication, nothing is referred to the spare-tire fastening structure for fastening the spare-tire to its receiving section by the bolt member and the nut member. U.S. Pat. No. 5,902,085 discloses a push-in type nut made of plastics comprising a plastic cap composed of a small flange and a hollow cylinder extending from the flange, and a plastic nut body composed of a pair of screw segments each having an internal thread formed inner surface thereof so as to cooperate with other screw segment to make up a complete nut as a whole and a pair of springs each extending from each screw segment to a base portion for biasing each screw segment upward from the base. This publication discloses the push-in type nut which is used in place of a conventional nut, but does not suggest anything about an application of the press-in type nut to the fastening structure for fastening the spare-tire to the spare tire receiving section.